Need the quote and the author

Hi,

Of course this is not quite related to SMTP......

There is a quote by someone from a time long ago which goes along the
lines of being conservative in what you generate and liberal in what you
receive.  In other words, make sure that you follow the specs to the
letter in what you generate, however try to deal with anything reasonable
that you can anticipate being thrown your way.

I need to know the exact quote and the author.  If it is documented
someplace that would be "nice" too.

Ed